Construction assembly for bridge cranes



Sept. 8, 1942. G. A. MITCHELL CONSTRUCTION ASSEMBLY FOR BRIDGE CRANES Filed Feb. 7, 1941 2 Sheets-Sheet l Sept. 8, 1942. G. A. MITCHELL CONSTRUCTION ASSEMIBLY FOR BRIDGE CRANES Filed Feb. 7, 1941 2 Sheets-Sheet 2 Patented Sept. 8, 1942 rss CONSERUCTIONS ASSEMBLY FOR BRlDGE CRANESA (ci. ros-i636 4 Claims.

The invention relates to traveling bridge cranesv and more particularly to a novel construction assembly for making such cranes.

One object of the invention is to provide a construction assembly for making cranes of the above general character which lends itself readily to sln'pment in knockdown form and which is adapted to utilize standard shapes for the bulkiest parts thereby avoiding the difficulty and expense involved in shipping such parts and enabling the other parts to be packed and shipped in the form of a compact lightweightkit.

Another object is to provide a construction assembly from which a bridge crane can be fabricated with a minimum of labor and with only the simplest of tools.

Anotherobject is to provide a construction assembly of standardized parts from which bridge cranes of various spans and capacities can be fabricated.

Still another object is to provide a construction assembly for making traveling bridge cranes adapted to utilize a standard motor driven hoistunitas the source of power for traversing the crane, thus materially reducing the cost ofl the i Itis also an object ofthe invention to provide I..

a traveling bridge crane of novel and improved construction which requires a minimum of over'- head clearance.

Other objects and advantages of the invention will become apparent from the'followng detailed description of the preferred embodiment illustrated in the'accompanyingdrawings in which:

Figure l is a perspective View of a traveling brdgecrane fabricated from aconstruction assembly embodyingV the' features of the invention.

Fig. 2' is a transverse sectional view ofV the crane showing details of one ofthe endtrucks.

Fig. 3 is a sectional view taken along thevv line 3-3-of Fig. 2 showing detailsof the traversingY mechanism.

Fig. 4 is a sectional View similar to Fig'. 3 showing the traversing mechanism. installed on the other end truckof the crane.

Fig. 5 is a side View of the shaft hanger form-- inga part of the construction-assembly.

Fig. 6 isa-perspective view of the beam clamping means provided on the end trucks.

Fig. 7 is a perspective view of a' traveling bridge crane similar to that shown in Fig; l butr equipped for manual traverse.

While the invention is susceptible of variousl modications and alternative constructions,- I have shown in the drawings and will herein describeY in detail the preferred embodiment, but it is to be understoodthat I do not thereby intend to limit the invention to the specific form disclosed but intend to cover allA modificationsendsA by wheeledV endl trucks Il and I2. which:

run on a track formed by spaced parallel rails-v I3.

arranged to be driven. by suitablepower or. manually operateddriving means forV traversing the crane along the track. The drivingwheels of the respective trucks are preferably coupled, as by a crossshaft I4 to maintain theA trucksin exact alinementat all times. Any suitable and.

well known type oflifting device or hoist may be supported on the bridge,v usually by means1 of' a trolley movable lengthwise thereof ortransversely ofthe direction ofv travel of' the cranen along its. track. With this arrangement",A the hoist may be spotted at substantially anypont within the area enclosed by the rails.

In carrying out the invention; I constructlthe.

unit V11 or, alternatively, a manual driving'unitA MA (Fig. 7) all of which areshown in heavy' lines in the drawings; constitute a construction assembly conveniently supplied inL kit form. It is' contemplated that the beam lrandshaft |47 will' be' obtained locally by the purchaser ofV the constructionv assembly to' reduce transportation and handling costs and the part's constituting' the assembly are so constructed that nof'drilling or` other machining operations are yrequired to u prepare' the, locally obtainedpartsf fori use.

The' trucks H and I2' are substantially alike exceptfor minor variations in the arrangement of the parts to= adapt them for usev at the leftA hand and rightv hand end'. of the' crane,.respecf tively, as-will appear presently. Eachc'onsstsfofv` As such cranes are usually installed. in an overhead position one wheel` of. each truck` is:

a frame comprising a pair of vertically disposed,

elongated side members I6 and I1 arranged in spaced parallel relation and joined together by cross members I8 to form a rigid structure. It will be observed that the side member I1 in each instance, is arranged on the inner side of the truck. This constitutes the main difference between the trucks.

At each end of the frame the side members are suitably apertured for the reception of axles upon which conventional flanged wheels 2I and 22 are journaled. The wheels are thus alined longitudinally of the truck, that is, they are arranged in tandem relationship for cooperation with one of the rails I3. Key plates 23 hold the axles in place in the frame.

To provide for attaching the beam I0 to the truck in the advantageous manner contemplated by the invention, the truck is constructed of generally U-shaped form. To this end the side members I6 and I1 are recessed in their upper edges leaving downwardly offset intermediate portions 25 connecting the end portions 26 in which the wheels are journaled. This construction provides for mounting a horizontal bearing plate 21 for the beam IU substantially below the center lines of the axles 20. The plate 21 extends over the side members, as shown in Figs. 1 and 2 and is welded or otherwise rigidly secured to the upper edges of the intermediate portions 25. By reason of the depressed bearing thus provided, the overhead clearance required for the beam is reduced to a minimum.

While any suitable connecting device may be utilized for securing the beam to the end trucks, it is preferred to employ clamping means which enables the beam to be used without any preparation other than cutting the same to the required length and which permits assembly by means of a simple tool such as a wrench. The use of this type of connection is made practicable by the arrangement whereby the beam is supported directly on the trucks, thus relieving the connecting means of the stresses imposed by the weight of the beam and the load carried thereby. Moreover, the arrangement for supporting the beam below the axes of the truck wheels substantially eliminates any tendency of the trucks to tilt from an upright position so that relatively little strain is placed on the clamping means from this source.

The clamping means is, of course, made to conform to the type of beam used for the crane bridge. For an I-beam such as that shown by way of illustration, the clamping means comprises a pair of generally L-shaped members 29 (Figs. 2 and 6) each comprising a horizontal base portion 30 and a substantially vertical beam engaging portion 3|. The members are mounted on the bearing plate 21 with the beam engaging portions in face to face relation for engaging the vertical web portion of the beam as shown in Fig. 2. Moreover, the base portion 30 of each member is recessed on its under side as at 32 to provide clearance for the ange of the beam and thus enable the members to t snugly against the same.

The clamping members, as herein shown, are secured to the bearing plate 21 by suitable bolts 33 projecting through elongated slots 34 in the base portion of the respective members. These slots are arranged to permit adjustment of the members toward and from each other to facilitate insertion of the beam therebetween and to permit their use with beams having webs of different thickness. Relatively thin, narrow shims 35 inserted under the outer edges of the clamping members, tend to tilt the members inwardly thus increasing the clamping action of the members when the bolts 33 are tightened. It will be apparent that this arrangement greatly facilitates the assembly of the crane as it is only necessary to insert the end of the beam between the clamping members, shift the members into engagement with the web of the beam and tighten the nuts on the bolts 33.

As pointed out hereinbefore, cranes of the type under consideration are usually traversed along the supporting track by driving a wheel of each truck. In the particular crane illustrated the wheel 2I of each truck is arranged to be driven and for this purpose is provided with a gear 40 located at one side of the flanged portion of the Wheel. Meshing with the gear 40 is a pinion 4I formed on or suitably secured to a stub shaft 42 (Fig. 4) journaled in a bearing provided by a boss 43 welded or otherwise suitably secured to an upwardly projecting extension 44 of the inner side member I1 of each truck. The bosses 43 are arranged so that the stub shafts 42 are substantially in alinement so that they may be drivingly connected by the cross shaft I4. To facilitate installation, the cross shaft is arranged to be connected with the stub shafts by coupling sleeves 45 secured to the respective parts as by set screws 45'.

The shaft hanger I5 previously referred to is provided for supporting the shaft I4 intermediate its ends. In the preferred form shown in Fig. 5, the hanger comprises a rigid arm 46 of angle iron or the like upon one end of which is mounted a bearing member 41 for rotatably supporting the shaft I4. The bearing member is preferably arranged for limited adjustment relative to the arm to avoid binding onthe shaft. Bolted or otherwise removably secured to the outer end of the arm 46 are a pair of clamping members 48 adapted to t over and frictionally engage the upper ilange of the beam I0. The clamping members enable the arm to be attached to the beam at any suitable point without requiring any drilling or other machining operations on the beam.

The driving wheel coupling arrangement above described is provided in each construction assembly whether intended for power or manual drive. If power drive is desired, one of the pinions 4I, in this instance the pinion journaled on the right hand truck I2, is provided at its outer end with a sprocket wheel 49 (Figs. 2 and 3) arranged substantially on the center line of the truck to be driven by the power unit P.

While the power unit P may be of any suitable character, in order to realize the economies of quantity production, it is preferred to utilize a motor driven hoist unit such as that disclosed in the Patent to Preston Whitcomb No. 2,211,873 granted August 20, 1940. This iunit as constructed is equipped with a toothed pinion 50 driven through reduction gearing by a reversible electric motor 5I. The pinion ordinarily serves as a sprocket wheel for the hoist chain and may be utilized without change or modification for driving the sprocket wheel 49 through the medium of an endless chain 52. The hoist unit is also equipped with motor controlling devices for controlling the direction of rotation of the motor. The control devices are arranged for remote operation either by means of suitable switches or by manually operable handles 53 carried at the ends of flexible cables of which one cable 5d is shown byway of illustration in Fig. 2. These controls require no changes to adapt the unit for operation in the bridge crane environment.

Suitable means is provided for mounting the power unit P n the end truck l2 with the pinion :31 alined with the sprocket wheel ,69. This means in its preferred form comprises a bracket 55 adapted to be bolted or otherwise removably secured to the bearing plate 21 of the end truck. The bracket terminates at its upper end in a pair of relatively inclined flanges 55 and 51 defining an upwardly opening cradle for the reception of the hoist unit. A vertical extension 58 of the flange 5l provides means for securing the power unit in place and for adjusting its position relative to the sprocket wheel 49. For this purp-ose the extension is apertured to receive a rod 59 threaded into the hole in the motor casing which is normally provided for the reception of a hoist supporting hook. A nut 59 threaded on the outer end of the rod tends to draw the hoist unit to the left as viewed in Fig. 2, thus acting to tension the driving chain 52. Thus, the hoist unit may be embodied in the bridge crane structure without change or modification and since such units are produced in quantity, the cost is relatively low as compared with the specially built power units ordinarily provided in cranes of this general character.

When the crane is to be manually driven, the power unit above described is omitted and a plain pinion 4l without the sprocket 49 may be provided. Included in the construction assembly is a wheel 6B adapted to be fixed to the shaft I4 in any suitable manner. The wheel is preferably of the well known type having a peripheral groove formed with spaced lugs for engagement with an endless chain 6I extending over the wheel. Thus the shaft may be rotated by operating the chain to drive the wheels 2l and thereby traverse they crane along its track. Conventional guides 62 are provided to hold the chain 6I on the wheel.

It will be apparent from the foregoing that the invention provides a novel and advantageous construction assembly from which bridge cranes of various spans and capacities may be fabricated with a minimum of labor and with only the simplest of tools. The construction assembly lends itself readily to shipment knockdown or kit form and permits the use of standard shapes for the bulkiest part of the crane such as the bridge and cross shaft. Thus, a substantial saving in transportation and handling costs may be realized by obtaining the beam and shaft locally.

The invention also provides a crane requiring a minimum of overhead clearance for its installation. Moreover, it permits the use of a standard motor driven hoist unit as a power source thus providing a relatively inexpensive means for powering the crane.

I claim as my invention:

1. In a construction assembly for making a traveling bridge crane, the combination of a pair of end trucks for supporting an I-beam of selected length, each of said end trucks comprising a pair of U-shaped side members having elongated horizontal portions and upwardly extending end portions, and a transverse plate bridging the upper edges of said horizontal portions of the side members centrally thereof, wheels mounted in said end portions of the side members at opposite ends of each truck, said transverse plates on the trucks providing seats for the opposite ends of the I-beam, and a pair of angle members bolted to the seating plate of each of said trucks on opposite sides of the I-beam and engageable with the bottom flange of the I-beam and also with the web portion thereof to detachably fasten the I-beam to the truck.

2. A construction assembly for making a traveling bridge crane comprising, in combination, a pair of end trucks adapted to support the opposite ends of an I-beam of selected length, each of said trucks comprising an elongated frame with supporting wheels journaled at opposite ends thereof and having an intermediate portion providing a seat for one end of the I-beam, means operative to removably clamp the ends of the I-beam upon the respective seats on said .trucks a spur gear rigid with one supporting wheel of each truck, a stud shaft journaled in each truck -frame and carrying a pinion meshing with the spur gear on such frame, and couplings operative to detachably connect the stud shafts of the two trucks with the opposite ends of a drive shaft of selected length.

3. A construction assembly for making a traveling bridge crane including, in .combination, a plurality of end trucks each comprising a pair of elongated side members forming a rigid frame with supporting wheels mounted at opposite ends thereof, a bridging member eX- tending between said side members substantially centrally of the truck frame and providing a seat for one end of a beam of selected length, means operative to detachably clamp the beam on said seat, a spur gear rigid with one of the 4supporting wheels of the truck, a pinion journaled in the truck frame and meshing with said gear, coupling means including a plain length of shafting of selected length drivingly connecting the pinions of the respective trucks, a power unit, a support for said unit detachably mounted on the bridging member of one of said trucks and disposed between the pinion thereon and the adjacent side of the beam clamped to said truck, means securing said power` unit to said support for adjustment toward and from said pinion, said power unit having a driving sprocket and the adjacent pinion having a rigid driven sprocket, and a chain drivingly connecting said sprockets.

4. A construction assembly for making a traveling bridge crane including, in combination, a pair of end trucks adapted to support a rigid beam of selected length, each of said trucks comprising a pair of elongated members having recessed central portions joined by a bridging member to formoa rigid downwardly opening channel section, said members having laterally spaced upwardly projecting end portions, wheels journaled in the opposite ends of the truck between said end portions, said bridging member providing a seat for one end of the beam, and clamping members adjustably secured to said bridging member on opposite sides of the beam and engageable therewith to detachably clamp the beam to the truck.

QEORGE A. MITCHELL. 

